find a post 1986 year 350 in junkyard (pay $250.00 to $1,200 depending on year, junk yard, and demand) and get the heads, intake, and computer. Order wiring from www.painlesswiring.com (about $180.00)and get O2 sensor diodes from www.summitracing.com (about $27.00 a piece)
a straight pipe is just that, a straight pipe, no mufflers or anything, it would be obnoxiously loud especially if you dual it out. Go with some Flowmaster mufflers for the low rumble, You need some back pressure in your exhaust system to keep your upper end of engine running smooth.